1. Technical Field
The present disclosure relates to printed circuit boards (PCBs), and particularly to a flexible printed circuit board (FPCB).
2. Description of Related Art
FPCBs are light, soft, thin, small, ductile, flexible and support high wiring density. FPCBs can be three-dimensionally wired and shaped according to space limitations. Flexible circuits are useful for electronic packages where flexibility, weight control and the like are important.
An FPCB may include a signal layer and a ground layer. Transmission lines may be arranged in the signal layer. Noise may be easily generated if the transmission lines are too close to the ground layer, which prevents the FPCB transmitting high speed signals. In addition, conventional FPCBs often have poor qualities for transmitting high speed signals because of failing to achieve required impedance.